kaolin.render.camera

API

kaolin.render.camera.generate_perspective_projection(fovyangle, ratio=1.0, dtype=torch.float32)

Generate perspective projection matrix for a given camera fovy angle.

Parameters

  • fovyangle (float) – field of view angle of y axis, \(tan(\frac{fovy}{2}) = \frac{y}{f}\).

  • ratio (float) – aspect ratio \((\frac{width}{height})\). Default: 1.0.

Returns

camera projection matrix, of shape \((3, 1)\).

Return type

(torch.FloatTensor)

kaolin.render.camera.generate_rotate_translate_matrices(camera_position, look_at, camera_up_direction)

Generate rotation and translation matrix for given camera parameters.

Formula is \(\text{P_cam} = \text{rot_mtx} * (\text{P_world} - \text{trans_mtx})\)

Parameters

  • camera_position (torch.FloatTensor) – camera positions of shape \((\text{batch_size}, 3)\), it means where your cameras are

  • look_at (torch.FloatTensor) – where the camera is watching, of shape \((\text{batch_size}, 3)\),

  • camera_up_direction (torch.FloatTensor) – camera up directions of shape \((\text{batch_size}, 3)\), it means what are your camera up directions, generally [0, 1, 0]

Returns

the camera rotation matrix of shape \((\text{batch_size}, 3, 3)\) and the camera transformation matrix of shape \((\text{batch_size}, 3)\)

Return type

(torch.FloatTensor, torch.FloatTensor)

kaolin.render.camera.generate_transformation_matrix(camera_position, look_at, camera_up_direction)

Generate transformation matrix for given camera parameters.

Formula is \(\text{P_cam} = \text{P_world} * {\text{transformation_mtx}\), with \(\text{P_world}\) being the points coordinates padded with 1.

Parameters

  • camera_position (torch.FloatTensor) – camera positions of shape \((\text{batch_size}, 3)\), it means where your cameras are

  • look_at (torch.FloatTensor) – where the camera is watching, of shape \((\text{batch_size}, 3)\),

  • camera_up_direction (torch.FloatTensor) – camera up directions of shape \((\text{batch_size}, 3)\), it means what are your camera up directions, generally [0, 1, 0]

Returns

The camera transformation matrix of shape \((\text{batch_size, 4, 3)\).

Return type

(torch.FloatTensor)

kaolin.render.camera.perspective_camera(points, camera_proj)

Projects 3D points on 2D images in perspective projection mode.

Parameters

  • points (torch.FloatTensor) – 3D points in camera coordinate, of shape \((\text{batch_size}, \text{num_points}, 3)\).

  • camera_proj (torch.FloatTensor) – projection matrix of shape \((3, 1)\).

Returns

2D points on image plane of shape \((\text{batch_size}, \text{num_points}, 2)\).

Return type

(torch.FloatTensor)

kaolin.render.camera.rotate_translate_points(points, camera_rot, camera_trans)

Rotate and translate 3D points on based on rotation matrix and transformation matrix.

Formula is \(\text{P_new} = R * (\text{P_old} - T)\)

Parameters

  • points (torch.FloatTensor) – 3D points, of shape \((\text{batch_size}, \text{num_points}, 3)\).

  • camera_rot (torch.FloatTensor) – rotation matrix, of shape \((\text{batch_size}, 3, 3)\).

  • camera_trans (torch.FloatTensor) – translation matrix, of shape \((\text{batch_size}, 3, 1)\).

Returns

3D points in new rotation, of same shape than points.

Return type

(torch.FloatTensor)